RTU Gas Heat — No Heat / Ignition Fault
- Interactive decision labs
- Built by working technicians
- Path-based verifiable certificate
- Exam preparation only
- Worldwide online
Commercial HVAC / RTU
~13 min
intermediate
The call
Rooftop unit is not heating. Thermostat is calling for heat. Blower may run, but there is no useful heat from the supply.
- Equipment
- Gas/electric packaged RTU, induced-draft gas heat section, ~8 years old
- Ambient
- 28°F
- Site notes
- Cooling worked earlier in the season. No recent gas service. Unit has power. Customer reports intermittent lockouts.
Decision 1 of 4
It is 28°F. The thermostat is calling for heat and the customer reports intermittent lockouts.
What do you check first on a no-heat RTU gas call?
Where this lab sits
This is one module lab from Commercial HVAC / RTU. The full path adds sealed systems, defrost, rack-system orientation and natural-refrigerant safety, each ending in a lab like this one.
Open the full pathNext lab: Residential No-Cool — Split System Not CoolingNext lab: Residential No-Heat — Gas Furnace Short Cycling on IgnitionNext lab: Frozen Coil / Airflow RestrictionNext lab: Superheat / Subcooling DecisionNext lab: Walk-in Cooler Not Holding TemperatureNext lab: Ice Machine Not Making IceNext lab: Reach-in / Prep Table Not Holding TemperatureNext lab: Walk-in Freezer Defrost FaultNext lab: Natural Refrigerant Safe-Handling DecisionNext lab: Rooftop Unit Not CoolingNext lab: RTU Economizer Stuck — No Free CoolingNext lab: RTU High Static — Low Airflow and Poor CoolingNext lab: RTU First Start-up Sequence